With roughly 94 teeth on display, sand tiger sharks swim with an open mouth. The teeth are visible even when the shark’s mouth is closed. Despite their toothy appearance, sand tiger sharks are not known for being aggressive. A habit of hovering in the water makes sand tiger sharks great ambush hunters. They are able to stay nearly motionless in the water by gulping air from the surface. This air gulping behavior is unique to sand tiger sharks.

With a mouth positioned on the underside of the body, southern stingrays dine along the soft ocean floor. Since most of their food is buried under sand, these stingrays will shoot water out of their mouth and flap their fins to uncover hidden prey such as smaller fish, mollusks, worms, shrimp and crabs. A stingray’s gills are on the underside of its body near its mouth. To breathe, holes near the eyes, called spiracles, draw water in, which is then expelled through the gills.